A new locality record for Radfordiella desmodi Radovsky, 1967 (Mesostigmata: Macronyssidae) parasitizing the vampire bat in Brazil

Macronyssid mites are ectoparasites of reptiles, birds, and mammals (mainly bats). Out of 35 genera in this family, Radfordiella Fonseca, 1948 is a genus from the Neotropical region with six valid species, found parasitizing phyllostomid bats. Only Radfordiella desmodi Radovsky, 1967 and Radfordiella oudemansi Fonseca, 1948 have been registered in Brazil. The present study provides a new locality record for the species R. desmodi, microscopy images to aid in the identification, and a distribution map.

A two-step metagenomics approach for prey identification from the blood meals of common vampire bats (Desmodus rotundus)

ABSTRACTThe feeding behaviour of the sanguivorous common vampire bat (Desmodus rotundus) facilitates the transmission of pathogens that can impact both human and animal health. To formulate effective strategies in controlling the spread of diseases, there is a need to obtain information on which animals they feed on. One DNA-based approach, shotgun sequencing, can be used to obtain such information. Even though it is costly, shotgun sequencing can be used to simultaneously retrieve prey and vampire bat mitochondrial DNA for population studies within one round of sequencing. However, due to the challenges of analysing shotgun sequenced metagenomic data such as false negatives/positives and typically low proportion of reads mapped to diet items, shotgun sequencing has not been used for the identification of prey from common vampire bat blood meals. To overcome these challenges and generate longer mitochondrial contigs which could be useful for prey population studies, we shotgun sequenced common vampire bat blood meal samples (n=8) and utilised a two-step metagenomic approach based on combining existing bioinformatic workflows (alignment and de novo mtDNA assembly) to identify prey. Further, we validated our results to detections made through metabarcoding. We accurately identified the common vampire bats’ prey in seven out of eight samples without any false positives. We also generated prey mitochondrial contig lengths between 138bp to 3231bp (mean=985bp, SD=981bp). As we develop more computationally efficient bioinformatics pipelines and reduce sequencing costs, we can expect an uptake in metagenomics dietary studies in the near future.

Potential attack of the common vampire bat (Desmodus rotundus) on nine-banded armadillo (Dasypus novemcinctus) in northern Oaxaca, México

El murciélago vampiro común, Desmodus rotundus, es un depredador que de forma obligatoria, se alimenta de sangre de vertebrados de un grupo diverso de presas, pero con preferencia a los mamíferos, tanto nativos como exóticos. El presente registro documenta la primera depredación potencial de un armadillo de nueve bandas, Dasypus novemcinctus, por D. rotundus en vida silvestre. La observación se registró en una cámara trampa colocada en un fragmento de crecimiento secundario de un bosque tropical perennifolio en Oaxaca, México. En una grabación de 10 segundos, observamos a un individuo de D. rotundus acechando y persiguiendo a un individuo de D. novemcinctus que busca alimento en la hojarasca. La presente observación, junto con otro estudio realizado en Brasil, donde un murciélago vampiro persiguió a un armadillo gigante Priodontes maximus, sugiere que los armadillos podrían ser presas de D. rotundus, pero la interacción es difícil de registrar en vida silvestre.

Gene losses in the common vampire bat illuminate molecular adaptations to blood feeding

Feeding exclusively on blood, vampire bats represent the only obligate sanguivorous lineage among mammals. To uncover genomic changes associated with adaptations to this unique dietary specialization, we generated a new haplotype-resolved reference-quality genome of the common vampire bat (Desmodus rotundus) and screened 26 bat species for genes that were specifically lost in the vampire bat lineage. We discovered previously-unknown gene losses that relate to metabolic and physiological changes, such as reduced insulin secretion (FFAR1, SLC30A8), limited glycogen stores (PPP1R3E), and a distinct gastric physiology (CTSE). Other gene losses likely reflect the biased nutrient composition (ERN2, CTRL) and distinct pathogen diversity of blood (RNASE7). Interestingly, the loss of REP15 likely helped vampire bats to adapt to high dietary iron levels by enhancing iron excretion and the loss of the 24S-hydroxycholesterol metabolizing enzyme CYP39A1 could contribute to their exceptional cognitive abilities. Finally, losses of key cone phototransduction genes (PDE6H, PDE6C) suggest that these strictly-nocturnal bats completely lack cone-based vision. These findings enhance our understanding of vampire bat biology and the genomic underpinnings of adaptations to sanguivory.

Serological Surveillance of Rabies in Free-Range and Captive Common Vampire Bats Desmodus rotundus

The control of vampire bat rabies (VBR) in Brazil is based on the culling of Desmodus rotundus and the surveillance of outbreaks caused by D. rotundus in cattle and humans in addition to vaccination of susceptible livestock. The detection of anti-rabies antibodies in vampire bats indicates exposure to the rabies virus, and several studies have reported an increase of these antibodies following experimental infection. However, the dynamics of anti-rabies antibodies in natural populations of D. rotundus remains poorly understood. In this study, we took advantage of recent outbreaks of VBR among livestock in the Sao Paulo region of Brazil to test whether seroprevalence in D. rotundus reflects the incidence of rabies in nearby livestock populations. Sixty-four D. rotundus were captured during and after outbreaks from roost located in municipalities belonging to three regions with different incidences of rabies in herbivores. Sixteen seropositive bats were then kept in captivity for up to 120 days, and their antibodies and virus levels were quantified at different time points using the rapid fluorescent focus inhibition test (RFFIT). Antibody titers were associated with the occurrence of ongoing outbreak, with a higher proportion of bats showing titer >0.5 IU/ml in the region with a recent outbreak. However, low titers were still detected in bats from regions reporting the last outbreak of rabies at least 3 years prior to sampling. This study suggests that serological surveillance of rabies in vampire bats can be used as a tool to evaluate risk of outbreaks in at risk populations of cattle and human.

VAMPIRE BAT DESMODUS ROTUNDUS SHELTERS IN THE CENTRAL REGION OF SÃO PAULO STATE, BRAZIL

The vampire bat Desmodus rotundus is the main transmitter of domestic herbivorous rabies, which causes economic losses in cattle raising, being a serious public health problem. The use of Geographic Information Systems (GIS) allows the spatial monitoring of these bats shelters, which is an efficient way to prevent and control rabies. This study located shelters of D. rotundus in the Eastern Center region of São Paulo state and identified the types of shelters used (natural or artificial), their proximity to water, sexual composition, and population estimated of the colonies. Searches were carried out by colonies of vampire bats in natural and artificial shelters during 2002 to 2004, covering 18 municipalities. After located, the shelters were georeferenced, being recorded the nature of the shelter (natural or artificial), use (shelters of males, maternities, digestive) and estimated population. The data were incorporated into a GIS, producing a thematic map of the shelter’s location and their distance from the local water bodies. There were found 1.567 D. rotundus distributed in 94 shelters, where only six shelters (6.38%) were natural (caves). Most shelters (79.78%) were sparsely populated, with up to 15 bats, including male shelters (46 shelters) and 30 maternities (63.82% of maternities). Five shelters (5.37%) had between 50 and 100 bats and only two shelters (2.15%) had a population greater than 100 bats. Six shelters (6.38%) were inhabited houses, which is a concern for public health, as these may constitute a source of dangerous contamination for domestic and human carnivores. All the shelters were at a distance of up to 2 km of rivers or streams. The high percentage of artificial shelters found is a consequence of the intensification of the anthropic changes that increase the supply of food and shelter to D. rotundus, which associated with a large drainage network favors the dispersion of this species of bat in the region. The proximity of all D. rotundus shelters to the drainage network corroborates other studies in São Paulo state, where the areas close to the main rivers generally favor the existence of a larger number of shelters.

Vampire Bat (Desmodus Rotundus) Abundancy and Frequency of Attacks to Cattle in Landscapes of Yucatan, Mexico

Desmodus rotundus is one of the wild animal species that has benefitted by habitat alteration and its population has increased due to livestock activities. Because vampire bats have caused economic losses to livestock production by feeding from these and other mammals and being the main rabies virus transmitter for cattle, population control campaigns have been implemented in Mexico. Yucatan is one of the seven most impacted States in Mexico by the number of cattle rabies cases per year, however, there is little research on vampire bat populations and attacks to cattle frequency patterns has never been analyzed so far. This study’s objective was to analyze the relationship between D. rotundus abundancy and number of bovines attacked in livestock landscapes in Yucatan. The study used data gathered by the State Committee for Protection and Promotion of Livestock in Yucatan through the National Campaign for Vampire Bat Population Control. Data from January 2014 to December 2017 was analyzed using Pearson correlation and bat abundancy and number of bovines attacked distribution maps. Greater abundancy of vampire bats and number of cattle attacked were observed in the central region of Yucatan, particularly in Izamal municipality. Positive correlation was found between 1) Abundancy of vampire bats and number of cattle in the region, 2) Total number of cattle and number of cattle attacked, and 3) Abundancy of vampire bats and number of cattle attacked. We can conclude that the relationship between abundancy of vampire bats and frequency of cattle attacked is positive.